This invention relates to a liquid handling system used in chemical analyses, and, more particularly, to such a system suited for automated operation with multiple functions.
Modern analytical chemical techniques often utilize a series of liquid handling steps that must each be applied to a large number of samples. For example, in solid phase extraction, columns of absorbent are used to separate the components of a liquid sample, and particular components are removed for further analysis. In a typical case, the column is first conditioned with the addition of a fluid. The sample is applied, possibly after being filtered, and the column is washed with a solvent to separate the component of interest. The component of interest is then eluted with yet another solvent and transferred to further analytical apparatus.
Some analytical laboratories process hundreds of samples using solid phase extraction or other techniques. Since the steps are highly repetitive, automated systems have been developed to reduce the manual labor involved in the liquid handling and processing. Such systems are commercially available and widely used.
Existing systems have shortcomings that limit their usefulness, however. One important problem arises in the wide variety of samples studied and the absence of a single standard size for the various columns, tubes, and vessels utilized in liquid handling operations. For example, an analytical laboratory may receive samples for analysis in a number of different-sized sample containers. It may be necessary to pour the sample into a single-size container that can be handled by the automated analytical apparatus. If a range of sizes are used in the analytical apparatus, there may be safety risks from splashing and spraying of fluids into the air, particularly when pressure is applied to the sample containers or columns in certain procedures. The result of this problem is that hand operations may be required that reduce the efficiency of the otherwise-automated analytical system.
There is a need for improved automated apparatus for performing analytical procedures without the need for operator intervention and minimizing the manual tasks required before, during, or after the analytical procedure. The present invention fulfills this need, and further provides related advantages.